High-power compressed-gas circuit interrupter with double-flow contact structure disposed within gas-directing casing



Dec. 12, 1967 c F CRQMER ET AL 3,358,102

HIGH-POWER COMPRESSED-GAS CIRCUIT INTERRUPTER WITH DOUBLE-FLOW CONTACT STRUCTURE DISPOSED WITHIN GAS-DIRECTING CASING Filed Aug. 24, 1964 6 Sheets-Sheet 1 Fl G. I.

HIGH PRESSURE GAS WITNESSES INVENTORS ChorIes E Cromer 8 Richard E, Kane BY m/fi k z' w W ATTORNEY Dec. 12, 19 67 c. F. CROMER ET Al- 3,358,102 HIGH-POWER COMPRESSED-GAS CIRCUIT INTERRUPTER WITH DOUBLE-FLOW CQNTACT STRUCTURE DISPOSED WITHIN GAS-DIRECTING CASING Filed Aug 24, 1964 6 Sheets-Sheet 2 Dec. 12, 1967 c MER ET AL 3,358,102

HIGH POWER COMPRESSED- S CIRCUIT INTERRUPTER WITH DOUBLE-FLOW CONTACT STRUCTURE DISPOSED WITHIN GAS-DIRECTING CASING 6 Sheets-Sheet 5 Filed 4, 1964 PM -NWLI Dec. 12, 1967 c, F. C MER ET AL 3,358,102

MPRESSE HIGH-POWER 00 D- CIRCUIT INTERRUPTER WITH DOU -FLOW CONTACT STRUCTURE DISPOSED ITHIN GAS-DIREC'I'ING CASING Filed Aug. 24, 1964 6 Sheets-Sheet 4 Dec. 12, 1967 c. F. CROMER ET AL 3,358,102

HIGH-POWER COMPRESSED-GAS CIRCUIT INTERRUPTER WITH DOUBLE-FLOW CONTACT STRUCTURE DISPOSED I WITHIN GAS-DIRECTING CASING Filed Aug. 24, 1964 6 Sheets-Sheet a Dec. 12, 1967 c. F. CROMER E AL 3,358,102

HIGH'POWER COMPRESSED-GAS CIRCUIT INTERRUPTER WITH DOUBLE-FLOW CONTACT STRUCTURE DISPOSED WITHIN GAS-DIRECTING CASING Filed Aug. 24, 1964 6 Sheets-Sheet 6 United States Patent HIGH-PUWER COMPRESSED-GAS CIRCUIT INTER- RUPTER WITH DOUBLE FLOW CONTACT STRUCTURE DISPOSED WITHIN GAS-DIRECT- ING CASING Charles F. Cromer Penn Township, Allegheny County, and Richard E. Kane, Monroeville, Pa., assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation 0t Pennsylvania Filed Aug. 24, 1964, Ser. No. 391,584 12 Claims. (Cl. 200-148) This invention relates generally to highpower compressed-gas circuit interrupters and, more particularly, to improved and simplified types of highly effective areextinguishing units for accomplishing high-power interruption.

A general object of the present invention is to provide an improved and highly-effective interrupting unit for interrupting considerable fault currents, such as say of the order of 75,000 amperes at a voltage of say, for example, 161 kv., and higher.

A more specific object of the present invention is the provision of an improved compressed-gas high-power circuit interrupter utilizing a minimum of parts and adaptable for ready assembly and disassembly with a minimum of operations.

Still a further object of the present invention is the provision of an improved compact three-pole compressedgas circuit interrupter utilizing a single grounded metallic tank as the enclosing structure, and having the three sets of entrance-type terminal bushings extending thereinto, thereby resembling in appearance a conventional oil tank-type circuit interrupter.

Still a further object of the present invention is the provision of an improved high-power circuit-interrupting unit utilizing a relatively low-value shunting resistance, in which improved interrupting means are provided for effectively and quickly interrupting the residual-current arc.

Another object of the present invention is the provision of an improved double-orifice-type separable contact structure utilizing compressed gas as the arc-interrupting medium, and effectively directing the gas flow in such a manner as to carry the arc terminals during low instantaneous values of current into the interior surfaces of the double-orifice contact structure and thereby quickly effect their axial movement immediately prior to a current zero so as to effect complete interruption at a current zero with consequent circuit interruption.

Another object of the present invention is the provision 3,358,102 Patented Dec. 12, 1967 ing and interrupting a residual-current are for high-power applications.

In accordance with one aspect of the instant invention, there is provided a compressed-gas arc-extinguishing unit utilizing a tubular hollow venting stationary contact, which is cooperable with a movable tubular venting contact. An insulating orifice-type interrupting chamber is provided having a resistor probe extending radially inwardly through one side wall thereof to contact the side of the aforesaid movable tubular venting contact. In addition, an axial eXtensiOn of the interrupting chamber is pro vided having a lower constricting end portion to eficctively direct gas flow through the movable tubular venting contact upon the establishment of a residual current are.

Further objects and advantages will readily become apparent upon reading the following specification, taken in conjunction with the drawings, in which:

FIGURE 1 is a side elevational View of a three-pole compressed-gas circuit interrupter embodying principles of the present invention;

FIG. 2 is an enlarged vertical sectional view taken through the interior of the tank structure of FIG. 1, substantially along the line IIII of FIG. 1, the contact structure being illustrated in the closed-circuit position;

FIG. 3 is a plan view in section, taken substantially along the line III-III of FIG. 2 indicating the general location and arrangement of the pairs of arc-extinguish ing units associated with the three pole-units of the circuit interrupter of FIG. 1;

FIG. 4 is an enlarged vertical sectional view taken through the improved compressed-gas arc-extinguishing unit of the present invention, the contact structure being illustrated in the partially open-circuit position;

FIG. 5 is a fragmentary view, somewhat similar to that of FIG. 4, but showing the interruption of the residualcurrent arc;

FIG. 6 is a top plan view of a gas-blast flow casting, which is utilized at the upper end of the arc-extinguishing unit of FIG. 4;

FIG. 7 is a sectional view of the gas-blast flow casting taken substantially along the line VIIVII of FIG. 8;

FIG. 8 is an end elevational view of the flow casting of FIG. 7;

FIG. 9 is a side elevational view of a casting constituting the receiver chamber for the improved arc-extingof an improved compressed-gas circuit interrupter having an improved stationary contact structure utilizing two concentrically-arranged contact and orifice elements, in which a movable tubular contact is thrust between the aforesaid two elements, so that high current values may readily be transmitted, and yet are transfer during circuit interruption is readily achieved by an inward radial flow of compressed-gas.

Still a further object of the present invention is the provision of an improved compressed-gas arc-extinguishing unit utilizing an orifice-type interrupting chamber in which a resistor probe extends through a side wall of the orifice chamber at a constricted point thereof, and in which a further interrupting section is associated with the afore said interrupting chamber to interrupt the residual current, which, for certain high-power applications, may approximate 4,000 amperes, for example.

Still a further object of the present invention is the provision of an improved compressed-gas arc-extinguishing unit of compact arrangement and effectively establishuishing unit of the present invention;

FIG. 10 is a top plan view of the receiver casting of FIG. 9;

FIG. 11 is a sectional view taken substantially along the line XI-XI of FIG. 10;

FIG. 12 is a sectional view taken substantially along the line XII--XII of FIG. 11;

FIG. 13 is an enlarged vertical sectional view taken through the blast-valve mechanism and the linkage therefor, associated with one of the pole-units of the circuit interrupter of FIG. 1; and,

FIG. 14 is a sectional view taken through a modified type of interrupter construction, the contacts being shown in the partially open-circuit position.

Referring to the drawings, and more particularly to FIG. 1 thereof, the reference numeral 1 generally designates a three-pole compressed-gas type of circuit interrupter. As shown, the circuit interrupter 1 comprises an enclosing grounded metallic tank 2 mounted upon a base frame 3, and having three pairs of terminal bushings 4, 4a, 5, 5a, 6, 6a extending therewithin.

Mounted upon the left-hand side of the tank structure 2 of the circuit interrupter 1, as viewed in FIG. I, is an operating mechanism compartment 8 enclosing a suitable operating mechanism, which may be of a conventional type. In other words, there is provided interiorly of the mechanism compartment 8 a suitable hydraulic, pneumatic or solenoid-type of mechanism, which will effect through a suitable bell-crank assembly horizontal recip rocable opening and closing movement of a horizontal pull rod, more fully described hereinafter.

It will be noted that there is provided a high-pressure reservoir tank 10 extending generally horizontally between the three pairs of terminal bushings. In addition, there is provided a compartment 12 enclosing suitable gas-conditioning and gas-compressor equipment. A laterally-jutting casing 14 encloses a suitable opening accelerating spring, which biases the horizontally-movable operating pull rod in a rightward direction, as viewed in FIG. 1, as more fully explained hereinafter.

With reference to FIG. 2 of the drawings, it will be noted that supported at the lower interior end of each of the terminal bushings is a compressed-gas arc-extinguishing unit, generally designated by the reference numeral 16, and comprising a gas-flow interrupter 17'and a laterally-spaced relatively low-value resistor assembly 18. A pair of movable tubular venting contacts 19 are clamped to the opposed extremities of a horizontally-extending cross-bar 20, which is actuated vertically in a reciprocable manner during the opening and closing operations by an upwardly-extending lift-rod assembly 21.

Extending generally upwardly from each circuit interrupter 17 is a blast tube 22, which interconnect, as at 23 (FIG. 13), and have the gas blast therethrough controlled by a blast-valve assembly 24. The blast valve 24, for each pole-unit, is actuated to an open position by means of a linkage 26 (FIG. 13), more fully described hereinafter.

Generally, the arrangement is such as to effect rightward opening movement of the horizontal pull-rod assembly 28 (FIG. 13), as assisted by the opening accelerating spring 29, to effect simultaneously upward opening movement of the blast valve 30, and downward opening movement of the lift-rod assembly 21 (FIG. 2). As a result, the movable tubular venting contacts 19 are carried downwardly by the cross-arm and lift-rod assemblies 20, 21, and effect are establishment within the individual circuit-interrupting units, while receiving a simultaneous blast of downwardlypassing compressed gas through the blast tubes 22, as caused by the opening of the blast valve 30 associated with each pole-unit of the interrupter.

With reference to FIGS. 2 and 13, it will be noted that the high-pressure reservoir tank 10 connects with three downwardly-extending high-pressure chambers 31, which provide the available high-pressure gas on the upstream sides of the three blast valves 30. As a result, upward opening movement of the three blast valves 30 will permit interconnection between the three high-pressure chambers 31 and the two blast tubes 22, which are associated with each of the three blast valves 30.

FIG. 3 illustrates the general location and arrangement of the six arc-extinguishing units 16 interiorly of the tank structure 2, and the association of the blast tubes 22, which supply high-pressure gas into the serially-connected arc-extinguishing units 16 of each pole-unit A, B or C.

FIG. 4 more clearly illustrates the internal contact construction of each circuit-interrupting unit 18. It will be noted that fixedly secured and clamped to the interior end 35 of each terminal bushing is an adaptor support casting 38 having bolted thereto, as by four bolts 39, to a flange portion 40 thereof, a plate portion 42 of a gas-receiver casting 43, which provides a seat for a stationary exhaust nozzle and contact structure, generally designated by the reference numeral 45.

FIGS. 9-12 more clearly illustrate the construction of the gas-receiver casting 43. With particular attention being directed to FIG. 10, it will be observed that there is provided an upper plate portion 46 having two gas-inlet apertures 47 provided therein, which intercommunicate into a gas-receiver chamber 50, as more clearly shown in FIG. 11 of the drawings. In addition, the upper plate portion 46 of the gas-receiver casting 43 is provided with a venting aperture 52 and a pair of mounting holes 53, the latter accommodating a pair of mounting bolts 56, which secure the stationary contact assembly into position, as shown in FIG. 4 of the drawings.

The lower end of the gas-receiver chamber 43 has an outwardly-extending flange portion 60 providing four mounting holes 61, which, in conjunction with bolts 63, secure into position a clamping ring 65, the latter, in turn, rigidly holding an insulating gas-flow directing interrupting chamber 7 0 into an operative position.

As shown in FIG. 4, the insulating gas-flow interrupting chamber 70 includes a first restricting portion 70a, a lower diverging portion 70b, and a final lower constricting tip portion 700. With further reference to FIG. 4, it will be noted that the movable tubular venting contact 19 enters through the lower orifice portion 700 of the gasflow interrupting chamber 70, and passes longitudinally upwardly thereof, so that the upper tip portion 19a thereof is thrust between two concentrically-related orifice and contact-finger assemblies 73, 74, as described in more detail hereinafter. The relatively stationary contact assembly 74 comprises a slotted generally tubular member, thereby furnishing resilient contact fingers having lower tip portions 80a, which resiliently bear inwardly upon the upper end 19a of the movable tubular venting contact 19. The internally-located orifice member 73 comprises a sleevelike member having two tapped apertures 73a disposed at the upper ends to accommodate the mounting bolts 56. In addition, it will be noted that the interiorlydisposed tubular orifice member 73 has the additional function of securely clamping the relatively stationary contact member 74 into a proper fixed position, the upper end of the latter seating within a recess portion 43a of the receiver casting 43, as more clearly shown in FIG. 11 of the drawings.

Encircling a flattened portion 70d of the insulating gasflow interrupting chamber 70 is a metallic resistor-probe ring having a spring pin 81 extending through one side thereof and into an aperture 82 provided in the side wall of the interrupter chamber 70. Situated generally diametrically oppositely the spring pin 81, and also serving to hold the resistor-probe ring 85 into proper position, is a resistor-probe assembly comprising a guide sleeve 91 threadedly secured to the ring 80, and accommodating an inwardly-biased resistor-probe 95. As shown in FIG. 4, the resistor-probe 95 bears inwardly upon the external side surface of the movable tubular venting contact 19, and provides a means of connection between the resistor assembly 18 and the moving contact 19. A flexible conductor is fixedly secured to the outer end of the resistor-probe assembly 90, and is connected to a terminal-plate portion 18a of the resistor assembly 18. The upper end terminal plate 18b of the resistor assembly 18 is secured by bolts 102 to the flange portion 40 of the contact adaptor 38 of the arc-extinguishing unit 16. It will, therefore, be apparent that the shunting resistor 18 is electrically in parallel between the relatively stationary contact structure 74 and the resistor-probe 95.

Disposed at the lower end of each blast tube 22, and serving the function of a manifold to transmit downwardly-flowing gas through the two inlet openings 47 of the receiver casting, is an inlet gas-flow manifold, generally designated by the reference numeral 110, and illustrated in more detail in FIGS. 6-8 of the drawings. With reference to these figures, it will be noted that the manifold casting includes an upper inlet neck portion 110a of reduced dimensions to accommodate an annular clamp 112, so as to fixedly secure the manifold casting 110 to the lower end of each blast tube 22.

With particular attention being directed to FIGS. 7 and 8 of the drawings, it will be noted that the manifold casting 110 has a laterally-directed vent opening 115, as provided by a downwardly-extending flange portion thereof, and a lateral exhaust opening 121 (FIG.

8) of semi-circular configuration, as is more readily apparent upon a study of FIG. 7 of the drawings. As a re sult, gas flow, which is directed upwardly through the interior 125 of the relatively stationary orifice member 73, will be turned at right angles, and will be directed outwardly by the manifold casting 110, so that the exhaust gases from each of the two serially-related arcextinguishing units 16 will be directed in opposite directions. This has the advantage that the exhaust gas from the stationary contact structures, in being directed in opposite directions, will prevent the possibility of flashover between the conducting manifold castings 110 when the circuit interrupter is in the open position, and voltage is imposed across the relatively stationary contact structures 74. It will, however, be noted that the configuration and internal construction of the manifold casting 110 is such as not to impede the downwardlyflowing gas blast, but yet provide the outwardly-directed exhaust vent opening 121, which cooperates with the exhaust opening 125 through the relatively stationary nozzle contact 73.

With particular attention beingdirected to FIG. 13 of the drawings, it will be noted that there is associated with each pole-unit A, B and C a latch lever 130 pivotally mounted, as at 131, to a downwardly-extending stationary bracket 135. The latch lever 130 has an operating arm 1341a, which is pivotally connected, as by a pivot pin 136, to the horizontally-extending and reciprocably-movable pull-rod 28. In addition, the latch lever 130 has a laterallyextending operating arm 138, which is pivotally connected, by a pivot pin 139, to a floating link 140, the latter, in turn, being pivotally connected, as at 142, to the upper extremity 21a of the lift-rod 21. The lift-rod 21, of course, is guided by stationary guide rollers, not shown, which are mounted upon the downwardly-extending support bracket 135.

With further reference to the latch lever 13d of FIG. 13, it will be observed that the upper extremity of the operating arm 138 has a ratchet portion 145 comprising a plurality of teeth 146, which make separable engagement with the tooth 148 of a pawl assembly 150, the latter being pivotally mounted upon a floating pivot pin 152. The pawl 150 is disposed between the furcations 1611 of a bifurcated blast-valve operating lever 161, which is pivotally mounted upon a stationary pivot pin 152a, and supports a blast-valve roller 170. The blast-valve roller 170 is aligned with the lower extremity 175 of the blastvalve stem 176. As shown in FIG. 13, the upper end of the blast-valve stern 176 cause upward opening move ment, at times, of the blast-valve 30 away from its stationary seat 1311 to thereby permit a flow of high-pressure gas to pass from the high-pressure chamber 31 into the manifold region 23, and subsequently downwardly through the two blast tubes 22..

After the latch surface 145, carried with the latch lever 130, has moved the pawl 150 and hence the blast-valve lever 161 in a clockwise direction about the stationary pivot pin 152a a predetermined extent, to effect blastvalve opening, due to the difference of the radius arms D D respectively, of latch lever 13d and pawl assembly 150, the latching tooth 145 will pull free from the pawl assembly 150 and thereby effect release of the blast-valve lever 161. Bleeder holes 30a permit equalization of pressurein regions 30!) and 23 to permit the blast-valve closing spring 195 to effect closure of the blast-valve 30.

As will be obvious, the continued clockwise rotation of the latch lever will effect continued downward opening movement of the lift-rod 21, bringing the movable contact structure 19 to the fully open position, as indicated by the dotted lines 200 in FIG. 2 of the drawings.

. During the closing operation, the counterclockwise rotative movement of the latch lever 130 about the pivot pin 131, as effected by leftward closing lateral movement of the pull-rod assembly 28, will effect upward closing movement of the lift-rod 21, and correspondingly closure of the movable contact structure in each of the arc-extinguishing units 16. Toward the end of the closing stroke, the ratchet surface of the latch lever 130 will ratchet past the pawl assembly 1511, thereby having no effect upon the blast valve 30. In other words, the blast valve 30 will remain closed during the entire closing operation. If the interrupter is being closed during fault-current conditions, the operating mechanism will effect reversal of the movement of the contact structure even before the breaker is fully closed, and by the provision of several teeth 146, a particular tooth may engage the pawl assembly during such a reversal, and immediately effect opening of the blast-valve assembly, which is desirable. Such a closeopen operation during fault-current conditions will require a blast of gas to extinguish the fault current then flowing through the interrupter, as well understood by those skilled in the art.

Certain features of the compressed gas arc-extinguishing units 16 and the blast valve operating mechanism and the linkage actuating the same are set forth and claimed in United States patent application filed Dec. 20, 1961, Ser. No. 160,957, by Robert E. Friedrich, Robert G. Colclaser, Jr., and Henrik Greger, and assigned to the assignee of the instant ap lication.

As the ratings of power circuit interrupters continue to rise, and the rate of rise of recovery voltage also rises, more and more effort is required to perform the interrupting function under short-circuit conditions. One method of attacking this problem is to divide the are into multiple breaks, and another is to modify the circuit at the time of interruption with resistors or capacitors, or a combination of both multiple breaks and paralleling impedances. The circuit interrupter of the present invention has an interrupting rating of 75,000 amperes. This is a current rating far in excess of any currents interrupted at the rating of 161 kv. The present invention is particularly concerned with a circuit-breaker construction utilizing multiple breaks and shunting resistors with a residualcurrent interrupting break and an isolating break.

In the particular circuit-interrupting construction of the present invention there are provided two identical circuit interrupters 16 suspended from high-voltage bushings, and serially connected by a moving cross-arm 20. These units are supplied with high-pressure gas, such as sulfur-hexafluoride (S1 gas from a common blast valve through insulating blast tubes. Generally, the interrupting unit 17 comprises a gas-receiver chamber, a moving contact metallic orifice 19, and a combination stationaryfinger contact assembly 74 and stationary metallic orifice 73. Finally, there is additionally provided a shunting resistor assembly 18 and a resistor contact assembly 95.

The interrupting function is performed on an opening operation as follows: When the circuit interrupter is tripped, as previously explained, the cross-arm assembly 20 moves downwardly toward the open position, and simultaneously the blast valve 30 is opened, thereby releasing high-pressure gas down the blast tubes 22 filling the receiver spaces 210'. As the moving contact 19 continues its opening movement toward the open position, an are 215 is drawn between the arcing tips of the moving contact 19 and the stationary contact fingers, which are is quickly transferred by the high-pressure gas from the fingers to the stationary metallic orifice 73. In this manner, arcing is established between the two interrupting nozzles 19, 73; and as current zero is approached, such arc is swept into the nozzles 19, 73. The hot ionized gases are swept out of the arcing space in both directions through the openings 125', 239 and 231. The are is quickly interrupted, and the current is transferred through the relatively low-ohm resistor assembly 18 and resistor-contact assembly 95 to the moving contact 19. As the moving contact 19 continues toward its fully open-circuit position, the high-power-factor current establishes an are 240 between the moving contact 19 and the resistor-assembly probe 95. This residual-current arc is low in magnitude and high in power factor, and is readily interrupted within the lower insulating orifice portion of the insulating flow director. The moving contact continues to its fully open-circuit position, as indicated by the dotted lines of FIG. 2, and thereby establishes an open-circuit gap between the moving contacts 19 and the interrupting assemblies 16.

A very important feature of the present novel circuitinterrupting construction is the highly-eificient gas-flow conditions which are achieved during the opening operation. First, it will be noted that the high-pressure gas, disposed within the receiver chamber 210, is directed in opposite directions through the stationary nozzle contact 73 and the moving nozzle contact 19 to carry the extremities of the established arc axially along the inner surfaces of such nozzles. This rapidly lengthens the are so that when the instantaneous value of the arcing current approaches zero, highly-efficient interrupting conditions are brought into place to achieve arc interruption. Moreover, and very importantly, it will be observed that the resistor-contact probe 95 is disposed intermediate the ends of the insulating fiow director 70, so that the gas flow is further directed by the divergent portion 70b and subsequently the constricting portion 700 into the interior of the moving contact 19, to thereby eitect a similar travel of the lower extremity of the residual-current are into the interior of the contact 19. Thus, when a current zero is approached, the residual-current arc is swept into the moving contact 19 and rapidly extinguished. In addition, the extending portion 70b shields and protects adjacent equipment from the heat and radiation of the arc.

From the foregoing description, it will be apparent that there is provided an eflicient, compact double-flow, double-nozzle-type of circuit interrupter, which can readily be combined with the movable cross-arm in a dead-tanktype of circuit interrupter to materially reduce the size and number of interrupters required for the severe application, previously described. The location and function of the resistor-current-type contact and the particular nozzle arrangement constitutes an efiective means to quickly interrupt the transferred residual-current arc after the fault-current interruption.

The provision of the divergent portion 70b of the in sulating gas-flow director 70 has a number of important advantages. First, it provides a clearance space between the moving contact 19 and the inner surfaces of the flow director 70 to prevent the deposition of metallic particles axially along the flow director 70, which would be conducive to early breakdown during the closing operation. Secondly, the divergent portion 70b effectively directs the gas flow, in combination with the restricted orifice portion 700 of the fiow director 70, to bring about highlyeliective interrupting conditions to be exerted upon the residual-current are established between the resistor-probe 95 and the tip 19a of the moving contact 19.

Moreover, it Will be noted that there is. provided a minimum of parts for rapid assembly and disassembly operations to be achieved. The gas flow is effectively directed with a minimum of obstruction into the gas-receiving chamber 210, and at this location is available for rapid venting in opposite directions through the nozzle contacts 73, 19 to not only effect are transfer from the stationary finger contacts 80, but also rapid arc elongation at a current zero. Rapid arc interruption is thereby obtained.

Although the present interrupting structure is suitable for a very severe interrupting application such as interrupting 75,000 amperes at 161 kv. rating, with a continuous current rating of, say 4500 amperes, it is to be clearly understood that it Will be obvious to those skilled in the art that certain aspects of the instant application are applicable to other circuit-interrupting structures of ditferent voltage and current rating. Merely for the purpose of illustration has the present invention been described as applied to a high-voltage, high-power circuit interrupter suitable for 161 kv. rating, with an interrupting capacity of 75,000 amperes. The residual-current arc may, for example, approach 4000 amperes in current magnitude.

It is to be clearly understood that the interrupting structure may be used without a shunting resistor and resistor-probe addition, Without in any way sacrificing any of the beneficial results achieved by the elongation of the are into the two nozzles 73, 19. For certain applications, where high-rates-of rise of recovery voltage transicuts are not encountered, there need be no necessity to resort to a resistor, and the modified interrupting structure of FIG. 14 may be used. Arc elongation and gas flow is indicated by the arrows. The theory of interruption is the same as that described hereinabove.

Although there has been illustrated and described specific interrupting structures, it is to be clearly understood that the same were merely for the purpose of illustration, and that changes and modifications may readily be made therein by those skilled in the art, without departing from the spirit and scope of the invention,

We claim as our invention:

1. In a fluid-blast circuit interrupter, in combination, casing means defining an inlet chamber and an adjoining gas-flow directing orifice portion having an exhaust opening, a relatively stationary contact structure having a nozzle exhaust means, associated therewith disposed within said casing means, a movable tubular venting contact cooperable with said relatively stationary contact structure and movable completely out of said exhaust opening to an isolating portion, the relatively movable contact structure constituting a sleeve valve means for inhibiting exhaust flow through the nozzle exhaust means and the movable tubularwenting contact until contact part, and fluid-pressure supply means for feeding pressurized fluid into said inlet chamber for subsequent ejection in substantially opposite directions through the nozzle exhaust means and the movable tubular venting contact to effect extinction of the established arc.

2. In a fluid-blast circuit interrupter, in combination, a relatively stationary contact structure having a nozzle exhaust means associated therewith, a movable tubular venting contact cooperable with said relatively stationary contact structure, means defining a fluid-pressure receiving chamber at least partially surrounding said relatively stationary and movable contact structure, the relatively movable contact structure constituting a sleeve valve means for inhibiting exhaust flow through the nozzle exhaust means until contact part, an insulating fluid-flow guide through which the movable tubular venting contact moves and withdraws in the fully open-circuit position of the circuit interrupter to an isolating position, an impedance probe contact extending through a side wall of the insulating fiuid-flow guide and disposed in near proximity to-the movable tubular venting contact, shunting impedance means electrically connected between the relatively stationary contact structure and said impedance probe contact, and fluid-pressure supply means for feeding pressurized fluid into said receiving chamber for subsequent ejection in substantially opposite direction through the nozzle exhaust means and the movable tubular venting contact to effect extinction of the established arc.

3. In combination, a generally cylindrical metallic gasreceiver chamber having an apertured end wall, a tubular nozzle exhaust and a surrounding stationary contact both secured to said end wall with the tubular nozzle exhaust in alignment with the aperture through the end wall, an insulating gas-flow guide secured adjacent the other end of said metallic gas-receiver chamber and constituting an extension thereof, a tubular venting movable contact movable completely through the insulating gas-flow guide and into and out of contacting engagement with said stationary contact, said movable venting contact movable to a separated isolating-position externally of said gasflow guide in the fully open-circuit position, high pressure gas-supply means for supplying gas under pressure into said gas-receiver chamber to exhaust in opposite directions through the tubular nozzle exhaust and through the tubular venting movable contact, and said tubular venting movable contact enveloping said tubular nozzle exhaust in the closed position for sleeve-valve action to initially conserve the rising pressure in the gas-receiver chamber.

4. In combination, a generally cylindrical metallic gasreceiver chamber having an apertured end wall, a tubular nozzle exhaust and a surrounding stationary contact both secured to said end wall with the tubular nozzle exhaust in alignment with the aperture through the end Wall, an insulating gas-flow guide secured adjacent the other end of said metallic gas-receiver chamber and constituting an extension thereof, a tubular venting movable contact movable completely through the insulating gas-flow guide and into and out of contacting engagement with said stationary contact, said movable venting contact movable to a separated isolating position externally of said gasflow guide in the fully open-circuit position, an impedance probe contact mounted in the side wall of said insulating gas-flow guide and in near proximity to the path of opening movement of the tubular venting movable contact, shunting impedance means electrically connected between the stationary contact and said impedance probe contact, and high-pressure gas-supply means for supplying gas under pressure into said gas-receiver chamber to exhaust in opposite directions through the tubular nozzle exhaust and through the tubular venting movable contact, and said tubular venting movable contact enveloping said tubular nozzle exhaust in the closed position for sleeve-valve action to initially conserve the rising pressure in the gas-reoeiver chamber.

5. The combination according to claim 3, wherein a dividing forked metallic gas-inlet coupling is secured to said cylindrical metallic gas-receiver chamber, and wherein said gas-inlet coupling has means defining a lateral exhaust opening in exhaust communication with the aperture through said end wall.

6. The combination according to claim 4, wherein the insulating gas-flow guide has a first constricted portion, and the impedance probe contact enters the gas-flow guide at said first constricted portion.

7. The combination according to claim 6 wherein the insulating gas-flow guide has an expansion portion beyond the first constricted portion, and wherein the gas-flow guide has a tight constriction at the free end thereof.

8. In combination, longitudinally-extending fluid-flow casing means having dual constricting portions, a movable tubular venting contact cooperable with a hollow venting stationary contact interiorly of said fluid-flow casing means, means for supplying compressed gas into said casing means to exhaust out of both the movable and stationary contacts, shunting resistance means including a resistor and a resistor-probe contact, said resistor-probe contact being located at one of said constricting portions, the resistor-probe contact extending through a side wall of said fluid-flow casing means into near proximity with said movable tubular contact, whereby the established main current arc is shunted by said resistor and the residual current are being drawn between the resistor-probe contact and the movable tubular contact interiorly of said fluid-flow casing means, and the movable tubular venting contact withdrawing out of said casing means to an isolated open-circuit position.

9. The combination according to claim 8, wherein the other constricted portion of the casing means is at the lower free end thereof to guide fluid into the movable tubular venting contact.

10. An arc-extinguishing unit for a compressed-gas circuit interrupter comprising, in combination, casing means providing an inlet chamber and an adjoining gasflow directing orifice portion having an exhaust opening, a generally tubular venting member (73) and a surrounding stationary contact assembly (74) disposed within said casing means for supplying a flow of highpressure gas to said inlet chamber, and a movable tubular venting contact (19) movable from an open-circuit isolated position completely externally of said casing means through said exhaust opening (70c) and to a closed position concentrically between said stationary contact assembly (74) and said venting member (73) to provide a closed sleeve-valve action prior to contact part, whereby the rising pressure during the interrupting operation in the inlet chamber is conserved and built up prior to contact part and not allowed to dissipate by a premature venting through the venting member (73) and the movable tubular venting contact (19).

11. An arc-extinguishing unit for a compressed-gas circuit interrupter comprising, in combination, casing means providing an inlet chamber and an adjoining gasfiow directing orifice portion (70) having an exhaust opening, a stationary contact assembly (74) disposed within said casing means, means for supplying a flow of highpressure gas to said inlet chamber, and a movable tubular venting contact (19) movable from an open-circuit isolatcd position completely externally of said casing means through said exhaust opening (700) and to a closed position into engagement with said stationary contact assembly, said gas-flow directing orifice portion (70) having a first construction (70a) at which a resistor contact is located, an expanded portion (70b) and a second constriction (70c), and a resistor assembly (18) electrically connected between the resistor contact (95) and the stationary contact assembly (74).

12. The arc-extinguished unit of claim 10, wherein the gas-flow directing orifice portion (70) has a first construction (70a) at which a resistor contact (95) is located, an expanded portion (70b) and a second constriction (70c), and a resistor assembly (18) electrically connected between the resistor contact (95) and the stationary contact assembly (74).

References Cited UNITED STATES PATENTS 2,481,996 9/ 1949 Grunewald et a1 200-148 FOREIGN PATENTS 923,361 2/ 1947 France.

242,105 4/ 1946 Switzerland.

ROBERT S. MACON, Primary Examiner. P. F. CRAWFORD, Assistant Examiner. 

1. IN A FLUID-BLAST CIRCUIT INTERRUPTER, IN COMBINATION, CASING MEANS DEFINING AN INLET CHAMBER AND AN ADJOINING GAS-FLOW DIRECTING ORIFICE PORTION HAVING AN EXHAUST OPENING, A RELATIVELY STATIONARY CONTACT STRUCTURE HAVING A NOZZLE EXHAUST MEANS, ASSOCIATED THEREWITH DISPOSED WITHIN SAID CASING MEANS, A MOVABLE TUBULAR VENTING CONTACT COOPERATBLE WITH SAID RELATIVELY STATIONARY CONTACT STRUCTURE AND MOVABLE COMPLETELY OUT OF SAID EXHAUST OPENING TO AN ISOLATING PORTION, THE RELATIVELY MOVABLE CONTACT STRUCTURE CONSTITUTING A SLEEVE VALVE MEANS FOR INHIBITING EXHAUST FLOW THROUGH A NOZZLE EXHAUST MEANS AND THE MOVABLE TUBULAR VENTING CONTACT UNTIL CONTACT PART, AND FLUID-PRESSURE SUPPLY MEANS FOR FEEDING PRESSURIZED FLUID INTO SAID INLET CHAMBER FOR SUBSEQUENT EJECTION IN SUBSTANTIALLY OPPOSITE DIRECTIONS THROUGH THE NOZZLE EXHAUST MEANS AND THE MOVABLE TUBULAR VENTING CONTACT TO EFFECT EXTINCTION OF THE STABILIZED ARC. 